The present invention relates to an image recording apparatus such ms an electrophotographic printer and a copying apparatus, and more particularly, to such apparatus using an image exposure from a cathode ray tube. The invention also relates to an exposure unit using a cathode ray tube in the image recording apparatus.
Some copying apparatus employ a photosensitive sheet as disclosed in Japanese Laid-Open Patent Application Kokai No.61-166573. In such copying apparatus, the photosensitive sheet is exposed with light that has been emitted from a light source and passed through a colored original, to form a latent image on the photosensitive sheet, and the latent image is then developed into a visible image by a wet-type developing device.
The above process however cannot be utilized in an electrophotographic printer employing a photosensitive sheet. Further, it has been difficult to construct a printer which makes use of high resolutional power which is inherent to the photosensitive sheet by relying upon the conventional process.
Further, there is known a copying apparatus for copying an image displayed on a CRT by applying a signal sent to the CRT to another printer. Another method of recording a CRT image has been to photograph the CRT image.
The copying apparatus employing another printer to copy the CRT display image is not of satisfactory quality, and the resultant image is of a fixed image. The photographing process has also been unsatisfactory in that it can only record still images and it is tedious and time consuming to photograph a CRT image. Recent CRT displays have a scrolling capability for continuously moving the displayed image in the screen up or down. There has been a demand for copying such a continuously scrolled CRT image. However, a suitable apparatus has not been available to meet such a demand.
Furthermore, it is known that when the image of an object is focussed on a surface through an optical lens, the brightness of the edge of the formed image is lowered due to the cosine fourth power law. Therefore, when an image displayed on a CRT screen is formed on a photosensitive recording medium through the optical lens, the brightness of the edge of the formed image is reduced. Heretofore, it has not been practiced to compensate for such a reduction in the brightness of the edge of the formed image on the photosensitive recording medium.